802.11 wi-fi handbook, Chapter 9 Wireless Lans in the network

What is Include in this Book

As discussed in Chapter 1, early forms of wireless LANs have been available since the mid-1980s. Standardized and interoperable WLANs have been shipping since 1997, and Wi-Fi products have been available since 1999. Despite this and the more than $1 billion spent worldwide annually on 802.11 products at this writing, WLAN deployments in the enterprise are still in their earliest days. Today, to the extent that WLANs are found in the enterprise, they tend to be limited deployments in places like conference rooms, cafeterias, and, naturally, the senior executive floors. Indeed, WLAN proliferation into vertical markets like retail, manufacturing, and warehousing greatly exceeds enterprise adoption. As evidenced by the sheer number of low-cost, easy-to-install Wi-Fi products available at computer retailers and catalogers, proliferation of wireless into residences and small offices is growing rapidly—in fact, far more quickly than into enterprises. Today’s enterprise deployments are almost experimental in nature, as enterprise IS (information services) professionals, managers, and staff gain familiarity with WLANs and come to understand how they can best integrate Wi-Fi into an overall enterprise information infrastructure.

In this chapter, we define enterprise WLAN deployments, making, at the functional level, a distinction between enterprise deployments and small office/home office (SOHO) deployments. We discuss the approach an enterprise typically takes when deploying a WLAN. We also outline the steps enterprise IS professionals should take to maximize the likelihood of a successful initial deployment, including a physical assessment of the facilities in which wireless is to be deployed (the site survey) and the capacity planning needed to provide the enterprise-level performance demanded by users. Given that in the enterprise an existing wired LAN already exists, we discuss how IS professionals best can integrate Wi-Fi into this overall infrastructure, where wireless adds a vital mobility element to a network and where it might be a replacement or alternative to more traditional wires. We also discuss how you can best leverage existing network management tools and practices from the wired world to most expediently bring a similar level of management to the WLAN.

A theme throughout this chapter is that 802.11 equipment should be considered a highly integrated network element, rather than simply tacked onto a LAN, whether the network is in the home office or resides within a large enterprise.

WHAT IS THE ENTERPRISE?

First and foremost, the Enterprise is, of course, a series of starships, all captained by dashing leaders and crewed by a pan-galactic collection of Federation officers. Having said that, a definition of the enterprise as it relates to WLAN deployments is probably more germane to this book. Like the Enterprise, many enterprises are large, consisting of, at minimum, hundreds of individuals, all of whom are users of the organization’s information infrastructure in some fashion. While many of these users may be located in a single headquarters building or campus, the enterprise is typically geographically distributed, with users scattered across a region, a continent, or even around the world.Chapter 9: Wireless LANs in the Enterprise

The fact that a user may be working out of a spare bedroom thousands of miles from the enterprise headquarters makes that user no less an enterprise user—indeed, it is these sorts of users who often most challenge IS professionals.

NOTE The average 802.11 sale to enterprises consists of three to five access points, because most enterprises worldwide are small businesses rather than the more widely publicized large corporations.

Certainly, large commercial entities around the world are considered to be enterprise-level organizations. The more expansive definition is one that includes any large organization with a common purpose where individuals are engaged in specific, complementary tasks—including managing the enterprise information infrastructure. By this definition, larger governmental entities on the city, county, state, and provincial level as well as on the national level are “enterprises.” Similarly, school systems, whether public or private, are enterprise organizations.
Stated another way, an enterprise is any organization that reaches the size at which it requires a dedicated staff of one or more IS professionals. The charter of this staff, no matter how small, is to make certain that the information infrastructure meets the needs of the organization and enables it to meet its goals—ideally, better than competitive organizations. And to remain competitive, leveraging new technologies to its advantage is a requirement for any organization, whether in the private or public sector. Wireless LANs are an excellent example—perhaps the best example available today—of an information technology that can have dramatic impact on the efficiency and effectiveness of an organization. Not surprisingly, IS professionals around the world are increasingly being charged with installing Wi-Fi, often on a trial basis with small pilot programs but with a mind toward a ubiquitous enterprise-wide deployment.

A SOHO Wi-Fi deployment presents few of the challenges associated with an enterprise deployment. As discussed in Chapters 5 and 6, the range of Wi-Fi devices, varying from a low of 60 feet to over hundreds of feet, is more than sufficient to cover even the largest of homes and small offices—even at the highest possible data rates. Indeed, if a home is so large as to require more than a single access point to achieve full physical coverage, it’s likely that the owner has the wherewithal to hire an IS professional to manage the installation. The number of users in a SOHO environment tends to be fairly limited. While it’s true that users of a SOHO LAN use the LAN to access other local computers, it is far more typical for users on a smaller LAN to access data from across the WAN, which can be cable, DSL, or even dial-up. This sets their performance expectations at fairly modest levels.

The enterprise is, of course, a completely different story. Typical corporate, governmental, and educational facilities, by their multistory nature alone, require more than a single access point to cover the entire building. In campus settings, the requirement can even be extended to include not just complete and reliable in-building coverage, but also WLAN availability between buildings. This opens up a whole host of challenges not found in SOHO deployments including roaming and channel reuse that will be discussed further in this chapter.In larger enterprises, users have come to expect a level of network performance that is consistent with a wired network, one that is often switched, providing dedicated bandwidth that is typically rated at 100Mbps—and occasionally faster. Given this level of expectation, the IS professional’s challenge is to provide the freedom and flexibility of wireless with performance and security that approximates that of the wired network.

In short, an enterprise is a relatively large organization with a common goal. The organization is typically in some form of competition with organizations with similar goals and, as such, employs information technology (among other tools) to gain competitive advantage. As such, the deployment of Wi-Fi in an enterprise presents challenges not found in other sorts of deployments and substantial consequences when things don’t go quite as planned.

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